Heart rate variability and fatigue in MS: two parallel pathways representing disseminated inflammatory processes?

Abstract

Background Fatigue is a disabling symptom of multiple sclerosis. Its biological causes are still poorly understood. Several years ago, we proposed that fatigue might be the subjective representation of inflammatory processes. An important step for a straight-forward evaluation of our model would be to show that the level of fatigue is associated with vagal activation. The heart rate is under partial control of the vagus nerve. Using power spectrum analysis allows to separate, at least partly, sympathetic and parasympathetic impact on heart rate variability. Methods This narrative review summarizes the evidence for heart rate variability changes in MS patients, their relationship with fatigue and disease course. To do this, we conducted a literature search, including 45 articles relevant to the topic treated in this review. Results We illustrate that (1) inflammation leads to a change in cardiac behavior during acute and chronic phases, both in animals and in humans; (2) MS patients show changes of heart rate variability (HRV) that resemble those during acute and chronic inflammation due to multiple causes; (3) existing evidence favors a set of specific predictions about fatigue and parallel HRV changes; and (4) that MS-related brainstem lesions or neurological impairments do not completely explain HRV changes, leaving enough place for an explanatory relation between HRV and fatigue. Discussion We discuss the results of this review in relation to our model of fatigue and propose several observational and experimental studies that could be conducted to gain a better insight into whether fatigue and HRV can be interpreted as a common pathway, both reflecting activated autoimmune processes in MS patients.

Acute combined effects of concurrent physical activities on autonomic nervous activation during cognitive tasks

“…In the absence of influence of PL, subjects’ HRV features underwent significant changes as the cognitive task load increased. The autonomic nervous system, consisting of the sympathetic and parasympathetic nervous systems, regulates the arousal level of workers and is closely related to fluctuation in HR ( Maiorana et al, 2022 ; Garis et al, 2023 ). The substantial reduction in the high-frequency value of HRV and the low-frequency value may be indicative of increased activity in the sympathetic nervous system, and vice versa .…”

Association between Daytime Sleepiness, Fatigue and Autonomic Responses during Head-Up Tilt Test in Multiple Sclerosis Patients

“…Recent studies have revealed a significant correlation between fatigue and CAD [ 51 , 52 ]. As previously reported, the present study demonstrated that MS patients were more fatigued than HCs, and both fatigue and age were inversely correlated with LF/HF response to the HUTT.…”

“…The progression of autonomic nervous system (ANS) dysregulation in MS entails a shift from mildly diminished sympathetic activity during the initial stages to a chronic phase characterized by increased basal sympathetic tone and autonomic imbalance. This state is frequently coupled with diminished sympathetic responsiveness to orthostatic challenges and a deficiency in parasympathetic function, as noted in progressive MS variants [ 52 ].…”

Staunch the Age Related Decline into Dementia, Cancer, Autoimmunity (POTS), Obesity, and Other Diseases with a Prebiotic, Probiotic, Postbiotic Triple Play

“…Cancer diagnosis and prognosis are linked to TNF-α [106], IL-1β [107,108], and IL-6. Low HRV can alert one to asymptomatic infection and inflammation [110,119], anxiety [111], depression [112,113], cognition and neurodegenerative disorders [114,115], psychosis spectrum disorders [116], cancer [117,118], cardiovascular disease [119,120], stroke [121,122], T2DM [123,124], severe Covid-19 [125], Long Covid [126][127][128], MS [129], SLE [130], and RA [131]. Central aka visceral adiposity (waist hip ratio, waist circumference) is negatively related to HRV and a much more sensitive indicator than BMI [133,134].…”